The Scottish Hydropower Resource Study says that there are 1019 financially viable schemes and a total of 128 new dams would be required.

Sites with capacities of more than 1MW totalled 176, and the total capacity possible being almost 313MW. Six of the sites were in the 5MW-10MW range (total capacity 36.2MW) and 170 in the 1MW-5MW band (total capacity 276.6MW).

The study identified 300 financially viable sites with capacities in the 500kW-1MW range (total capacity 193.2MW), and 543 sites with capacities below 500kW (total capacity 151MW).

Scotland has 1380MW of installed hydro capacity, excluding pumped storage, a further 104MW under construction, just over 5MW with consent to build and 16.1MW in planning. A further 27.2MW is in the scoping stage.

The new study estimated there are 36,252 sites that could give rise to practical and technically feasible projects, and they have a total potential power of almost 2.6GW to generate 10,644GWh annually. The theoretical maximum levels of each at the beginning of the study were 5.4GW and 47,300GWh per year, respectively.

Constraints used in the study included allowances for natural heritage protection and the capacity and extent of the transmission grid. The 657MW included 227MW of resource potential in areas of natural heritage after allowing for a ‘modest”’ level of protection, before the application of which the comparable figure was 357MW from 337 sites.

In terms of the grid, based on previous studies the new study estimated that about a third of new hydro power generation would not be able to be accommodated by the existing network. The bottleneck in linkages and capacity would need addressed before the full 657MW could be exploited.

The study was carried out on behalf of the Scottish Government to assist the Hydro Sub Group of the Forum for Renewable Energy Development in Scotland (FHSG).

A consortium undertook the study, comprising Nick Forrest Associates, the Scottish Institute of Sustainable Technology (SISTech) and black-veatch (B&V).

The data in the study were examined using the GIS-based computer model Hydrobot, from Nick Forrest Associates and previously called Hydro-Electric Location and Planning (Help) which came out of an award-winning MSc dissertation for the University of Edinburgh, in 2006. The analyses and simulations were verified against a number of existing hydro plant sites. The software focused on establishing capacity not cost.